1. Field of the Invention
The present invention belongs to a technological field of a magnetic resonance imaging diagnosis system (MRI system), and relates to a magnetic apparatus having a superconductive electromagnet for generating a uniform static magnetic field and gradient-magnetic-field coils for generating a gradient magnetic field.
The MRI system is an imaging diagnosis system utilizing a nuclear magnetic resonance phenomenon in materials, which enables imaging ingredients or structures of a subject body laid under a uniform static magnetic field region generated by the superconductive electromagnet, etc.
The MRI system comprises: a superconductive electromagnet for generating a uniform static magnetic field region; a pair of gradient-magnetic-field coils and a gradient-magnetic-field power supply for generating a gradient magnetic field having gradients in the three directions “X”, “Y”, and “Z” (given the Z directions to be the uniform static magnetic field) in the uniform static magnetic field region; a high-frequency coils and a high-frequency-magnetic field generator for emitting high-frequency waves to a subject laid in the uniform static magnetic field region and receiving a nuclear magnetic resonance signal from the subject; and a computer for digitizing the received nuclear magnetic resonance signal by the high-frequency coils so as to execute an imaging process.
2. Description of the Related Art
In a first conventional MRI system (for example, refer to Japanese Laid-Open Patent Publications 2002-17705), a vacuum container for housing superconductive coils is in annular form, and gradient-magnetic-field coils are located in the central space of the vacuum container and fixed to an iron yoke via a gradient-magnetic-field-supporting member.
Moreover, in a second conventional MRI system (for example, refer to Japanese Laid-Open Patent Publications 2002-52004), a vacuum container for housing superconductive coils is in annular form, and gradient-magnetic-field coils are located in the central space of the vacuum container and fixed to a flat-plate-gradient-magnetic-field-coil-supporting member via a cylindrical gradient-magnetic-field-coil-supporting member. The flat-plate-gradient-magnetic-field-coil-supporting member is maintained apart from the vacuum container by being coupled with a fixed pillar.